POS0281 FLUCTUATIONS IN SERUM URATE ARE RELATED TO GOUT FLARES IN THE NOR-Gout STUDY
Authors: T. Uhlig, L. Karoliussen, J. Sexton, T. K. Kvien, E. A. Haavardsholm, F. Perez-Ruiz, H. B. Hammer
Journal: Annals of the Rheumatic Diseases (2022)

Background Urate lowering therapy (ULT) is expected to prevent new gout flares, but flares still do occur during the first year, and could be related to fluctuations in serum urate (SUA), being a result of proinflammatory signals. Knowledge on the relationship between fluctuation in SUA and gout flares is limited. Objectives To study how fluctuation in SUA is related to gout flares in the first year of ULT. Methods In a prospective observational 2-year study 211 included patients with crystal-proven gout were evaluated for flare frequency. Patients were frequently followed during ULT (allopurinol or febuxostat) with monthly dose escalation until SUA was at target (&lt;360 µmol/L or &lt;300 µmol/L if tophi), and met also for visits at 3, 6, 9, 12 during year 1 and at year 2. Self-reported flares were continuously registered at all study visits. Fluctuations in SUA were defined with various measures of SUA: a.) sum of changes between all consecutive visits over the whole 2-year period as a global measure, b. SUA change during 3-month visits at year 1 and during year 2. Further, the frequency of patients exceeding SUA changes with threshold &gt;30, &gt;60 and &gt;90 µmol in these periods was calculated. Fluctuations in SUA were then related to self-reported flares during the same 3-month periods year 1, and the whole years 1 and 2. Results Age was 56.4 (SD 13.7) years, 95.3% were males, disease duration 7.8 (SD 7.6) years. SUA decreased from mean 500 µmol/L at baseline to 311 µmol at 1 year and 324 µmol/L at year 2. Flares were seen in year 1 in 81.2% (155/186) and year 2 26.0% (45/173) of patients. The total sum of SUA changes over 2 years as a global measure for individual SUA fluctuation was related to flares in all 3-month periods during year 1 (Table 1) and for year 1 overall (Figure 1), but not for year 2. Table 1. Flares and fluctuation of serum urate (SUA) measures during defined observation periods. Flare period (Mths) N Sum of all SUA changes (mean) SUA change (mean) &gt;30 µmol/L SUA change (% patients) &gt;60 µmol/L SUA change (% patients) &gt;90 µmol/L SUA change (% patients) 0-3 Flare + 63 467* 141* 88.1 83.1 67.8 Flare - 148 388 165 95.5 91.5 80.8 3-6 Flare + 91 459** 19 38.8 28.2 10.6 Flare - 120 375 17 39.4 24.5 14.9 6-9 Flare + 56 482* 10 49.0** 25.5 25.5 Flare - 155 386 26 26.5 15.5 15.5 9-12 Flare + 70 470* 4 32.2 16.9 11.9 Flare - 116 406 9 22.6 9.4 6.6 0-12 Flare + 155 445* 193 98.0 94.0 90.7* Flare - 36 345 160 91.7 86.0 75.0 12-24 Flare + 45 411 13 24.4 11.1 6.7 Flare - 128 449 14 25.8 11.7 4.7 *P&lt;0.05, **P&lt;0.01 for comparisons +/-Flare Other measures of SUA fluctuation (SUA change during periods, and exceeding thresholds of change) were generally not related to incidence of flares, neither were sensitivity analyses for incidence of flares in periods succeeding observed SUA fluctuations. Conclusion Fluctuation in SUA, defined as the total sum of mean SUA changes between all study visits, was related to gout flares during year1. Our findings support that a pattern of SUA fluctuation is related to gout flares. Disclosure of Interests Till Uhlig Speakers bureau: SOBI, Consultant of: Grünenthal, Lars Karoliussen: None declared, Joe Sexton: None declared, Tore K. Kvien Speakers bureau: AbbVie, MSD, UCB, Hospira/Pfizer, Eli-Lilly, Roche, Hikma, Orion, Sanofi, Celltrion, Sandoz, Biogen, Amgen, Egis, Ewopharma, Mylan, Grant/research support from: BMS, Espen Andre Haavardsholm Speakers bureau: Pfizer, UCB, Eli Lilly, Celgene, Janssen-Cilag, AbbVie, Gilead, Fernando Perez-Ruiz Speakers bureau: Algorithm, Alnylam, Astellas, Arthriti, Menarini, NMD, Parexel, Hilde Berner Hammer Speakers bureau: AbbVie, Lilly, Novartis